It is often desirable to perform a biopsy to sample selected tissue from a patient for medical evaluation. For example, biopsies can be useful in diagnosing various forms of cancer and other diseases affecting a localized area of tissue. However, many existing biopsy devices use only about half or less of their diameter to obtain tissue. Other devices that obtain a full cylinder or “full core” of tissue have difficulty in withdrawing tissue, and/or in maintaining the physical state of the tissue so as to provide an accurate assessment of tissue condition. With respect to the latter difficulty, one desire in obtaining tissue samples is to obtain the tissue with minimal physical changes, such as from scoring or mashing by the device. Physical characteristics of tissue, such as placement or orientation of cells or tissue, may be as important or more important than the chemical or biological characteristics (e.g. presence of malignant cells or by-products). Existing full-core biopsy needles can physically damage tissue as the sample is being obtained in vivo, and further damage to the sample (e.g. pulling the sample apart) can occur as the sample is pulled or picked out of the needle.
Accordingly, there is a need for a biopsy apparatus and method that are better able to provide samples that are easier to study.